Manufacture of aryl amines



l halides, and (2) the action of alkyl halides upon reagents as Sulfuricacid, phosphoric id, alumi- Patented Jan. 4, 1938 UNITED STATES PATENTOFFICE MANUFACTURE or ARYL AMIINES Charles L. Thomas, Chicago, 111.,assignor to Universal Oil Products Company, Chicago, 111., a corporationoi Delaware No Drawing. Application September 23, 1933, Serial No.690,761

Claims. (01. 260-1305) I This invention relates more particularly tocovered by crystallization from suitable solvents, the manufacture ofaryl amines containing alkyland the nitro bodies are then reduced, forexamsubstituting groups in the nucleus. pie, with iron powder andhydrochloric acid, to

In a more specific sense the invention has refform the desiredtoluidine. The course of the 5 erence to an improved process forproducing reactions in these two general steps is indicated 5 alkylatedtaryliamiaiiies whereby the number of by the following equations: separae s eps 5 re uced and the yields of alkylated products are considerablyhigher than those CH3C5H5+ O= =-CH C H,NO H O gflaainable by methods atpresent known in the 32% nitm'wl'mls m The aryl or aromatic amines,which term is used a 4 z+3H2r CH C I-l Nl-l,+2H,0

in its broadest sense to include mono or polymlmdues nuclear ringhydrocarbons containing any num- Another method of producing toluidinesfrom her of amino groups, constitute an important toluol consists infirst halogenating the ring and class of compounds on account of theiralkaline then converting the h o n e p d into reaction which enablestheir ready solution in the amine by treatment with ammonia under acidssuch as sulphuric, phosphoric and hydropressure. The steps in thisprocess are shown chloric acids, which solutions may be madethe by thefollowing equations: starting point for the manufacture of differentcompounds, particularly the aniline dyes which gfig gk i i fi ig gg areof great'commercial importance. The arorine toluol chl io matic vaminesare also the base materials for the manufacture of a large number ofspecial syn- +H thetic chemicals such as various drugs, flavoringamtoluidino materials, perfumes, antiseptics, etcetera. "101118 To deveop the character f e present p A third method or manufacture consists iness as a p v t v older processes a sulfonating the toluol with strongsulfuric acid ri f m nti n will be m de f h steps n some and thentreating the alkaline sulfonate with of h m n ra y wn and commonly usedsodamide according to the following equations: methods of' manufacturingthe alkylated aryl amines which constitute its desired product.CHacaHs+HZSO4=CH3CGHO3H+H2O The manufacture of alkylated aryl amineswlmlsumm add such as, for example, the toluidines which are shnplestmembers of this class may be accom- CH3C6H4SO3N3+N3NH2=CH3C6H4NH2+N32SO4plished (1) by the successive alkylation and Sodemids toluidinoaminization of the benzol'ring, (2) the methyla- S tion of aniline or(3) the aminization of toluol. This method is iflic l and dangerous nThese steps in many cases conflict so that yields count of the use ofsodamide which reacts exof toluidines representing the general class ofplosively with water which may accidentally be alkylated aryl amines istoo low for the process present. to be of any economic Value-Considerable difficulties are encountered in di- 49 In regard to themanufacture of alkylated rectly alkylating aromatic amines with olefinsmatics' these may be produced by several meth' owing to their reactivitywith the catalytic agents examples of which are: (1) The action ofemployed which are usually of an acid or metalsodium-on molecularmixtures of alkyl and aryl lie chloride character and may comprise sucharomatics in the presence of aluminum and simimum chloride etcetem Forexample, aniline lafly acting chlorides readily reacts with sulfuricacid, phosphoric acid, one method of making alkylated aryl amineshydrochloric acid, aluminum chloride, etcetera, is exemplified by theproduction of tomldmes to form water, alcohol or ether insoluble addifmmi gfifig g gf $31 52: 2; tion compounds and in the case of sulfuric acidzigii i f ig f T011101 is fir t also undergoes a certain amount ofsulfonation trated by a. mixture of sulfuric and nitric acids d pe d ngupon the conditions of treatment.- In under proper conditions forforming maximum he present process the alkaline characteristics yieldsof mono nitro toluols, which are then reof aryl amines are neutralizedprior to alkylating so that the common alkylating catalysts may beemployed with good results.

In one embodiment the invention comprises the manufacture of alleviatedaryl amines by the following steps: (1) Treatment of aryl amines withacetic acid to form acyl derivatives, (2) treatment of the acylcompounds with olefins in the presence of acid or metal salt catalyst,(3) hydrolysis of the alkylated acyl products to form alkylated arylamines and regenerate acetic acid for reuse.

The three steps comprised in the present process are typified by thefollowing equations which show the use of the simplest base compoundsand typical catalytic and hydrolyzing reagents:

(1) CsH5NH2+CH3COOH= aniline acetic acid CsHsNHCHaCO-l-HzO acetanilide(2) CcHsNHCHaCO+C2H4=CsH5CeH4NHCH3CO ethylethyl acetanilide (3)C2HsCsH4NHCH3CO+H20= C2H5CsH4NH2+CHaCOOH ethyl aniline acetic acid Step(1) may be effected by using glacial acetic acid, acetic anhydride oracetyl chloride, with suitable variations in operating and treatingconditions which are generally well known in theduced to a suitablepoint, usually in the neighborhood of 0 to 40 C. and either a singleolefin or a mixture of olefins such as may be present in the hydrocarbongas mixtures produced in oil or gas cracking processes is introducedinto the acid solution. To insure efiective and complete action thesolution should be mechanically agitated.

After completion of the alkylation the alkylated compound may berecovered either by diluting the acid with water, which throws thecompound out of solution, or by extracting the acid with some suitablesolvent such as, for example, carbon tetrachloride, orthodichlorobenzol, etcetera, the desired compound then being recovered byboiling off the solvent.

A generally similar procedure to that outlined above may be followed'with ortho phosphoric acid using concentrations from approximately 90to 100%.

When using such alkylating catalysts as aluminum chloride which is solidat the preferred low temperatures employed, the alkylation may be aidedby using various solvents which are inert to the compounds undergoingreaction and suf-- ficiently fluid. Examples of such solvents are carbontetrachloride, ethylene dichloride, ortho dichlorobenzene, chloroform,nitro benzol, etc. The procedure when using solvents consists indissolving acyl-aromatic amines in the solvent,

adding a finely divided metal chloride such as,

in olefin-containing gas until the absorption of olefins indicates thatthe desired degree of alkylation has taken place. The insoluble metalsalt and any sludge reaction products are then allowed to settle, thesolution of alkylated compound is decanted or filtered and the productrecovered as before as a residue from the evaporation of the solvent.The alkylated acyl aromatic amines thus obtained are then subjected tohydrolysis with caustic alkalies to remove the acyl group and producethe desired aromatic amine.

A number of different catalytic reagents both of an acid and a salinecharacter are mentioned above but the process is not limited to thespecific reagents enumerated but may employ any catalyst of suitablecondensing activity. The alternatives, however, will each exert its ownpeculiar eifect upon the speed and course of the reactions in any givencase so that they are not to be considered as exact equivalents.

The present process in one of its special application makes possible theproduction of alkylated derivatives of the nitrogen bases which ocour inthe tars produced by the distillation of various naturally occurringcarbonaceous materials such as, for example, coal, lignite, peat, shale,etcetera. Without the step of acetylating the aromatic amines, theiralkylation would be impossible by ordinary methods on account oftheformation of stable and insoluble compounds with strong acids such assulfuric and phosphoric acids and with condensing salts such as aluminumchloride.

The invention is not limited to the use of acetic acid in the first stepas previously shown, but homologs of this acid such as propionic acid,butyric acid, etcetera, may be employed and also benzolc acid and itshomologs. Thus, after the first step of the process compounds of thefollowing character may be alkylated: Acetanilide, acetnaphthylamines,acetanthraquinoneamines, benzanilide, acet-toluidines, diacetbenzidine,etcetera.

In the second step of the process any olefin or mixture of olefins maybe employed such as, for example, ethylene, propylene, the butylenes,amylenes, etcetera, and also compounds of a mixed olefinic-aromaticcharacter such as indene and styrene.

The following examples are offered as illustrations of the resultsobtainable by utilizing the reactions comprised within the scope of theinvention:

Example 1 100 parts by weight of acetanilide (produced by the directinteraction of aniline and acetic acid) is dissolved in approximately400 parts by weight of carbon tetrachloride, and to the solution about100 parts by weight of anhydrous aluminum chloride is added. Thesolution is then treated by introducing ethylene gas until a point isreached where the absorption rate is substantially zero.

The aluminum chloride sludge is settled, the carbon tetrachloride isdistilled off and the recovered alkylated acetanilide then hydrolyzed toproduce a mixture of ethyl anillnes, the yield being between 85 and 90%of the theoretical corresponding to the production of 77 parts by weightof the alkylated amine.

Example 2 100 parts of acetanilide is dissolved in about 400 parts byweight of 100% phosphoric acid.

After warming to 40 C. to hasten solution, cooling is applied tomaintain, the temperature at approximately 30 C. during the introductionof gaseous propylene. After substantially complete saturation withpropylene, the acid solution is diluted with about 6 volumes 01' waterand extracted with carbon tetrachloride, the steps from this point beingsimilar to those indicated in Example 1.- The yield in this case is 85%of the theoretical and consists of 85 parts by weight of a mixture ofisopropyl anilines, principally the ortho and para compounds;Approximately similar results are obtainable using concentrated suliuricacid in place ot phosphoric acid.

Example 3 forming a mixture of butylene propion anilides.

After the reactions are complete the semi-solid sludge is settled andthe separated solution is distilled to remove solvent, the alkylatedproduct being then recovered as a residue and subjected to hydrolysis toform the desired alkylated amine which in the present case is a mixtureof various butyl anilines, the yield being 88% of the theoretical andcorresponding to 59 parts by weight of the desired compounds.

The character of the present invention is disclosed in the precedingspecification and its value is shown by a consideration of the numericaldata presented but neither is to'be considered in the light of imposinglimitations upon its broad scope.

I claim as my invention:

1. A process for alkylating an alkyl-iree aeromatic amine, whichcomprises treating a primary aryl amine with a mon'o-carboxylic acid toform an acyl derivative, subjecting the acyl derivative to treatmentwith an olefinic hydrocarbon in the presence oi a condensation catalyst,and hydrolyzing the resultant compound to form the alkylated aryl amine.

2. A process for directly allgylating an alkylfree aromatic amine, whichcomprises treating a primary aryl amine with a mono-carboxylic acid toform an acyl derivative, subjecting the acyl derivative to treatmentwith an olefin in the presence a catalyst comprising essentiallyaluminum chloride, and hydrolyzing the resultant product to form thealkylated aryl amine.

3. A process for directly alkylating an alkylfree aromatic amine, whichcomprises treating a primary aryl amine with a mono-carboxyllc acid toform an acyl derivative, subjecting the acyl derivative to treatmentwith an olefin in the presence of a catalyst comprising essentially aninorganic non-oxidizing mineral acid, and hydrolyzing the resultantproduct to form the alkylated aryl amine.

4. A process for alkylating an allgyl-free aeromatic amine, whichcomprises treating a primary aryl amine with a mono-carboxylic acid toform an acyl derivative, subjecting the acyl derivative to treatmentwith an olefinic hydrocarbon in the

